Have a look inside of your boot.ini file on the working and non-working drives. This is located in the root of the C: drive and is hidden and protected. To show this file:
In any Explorer window, click Tools > Folder Options.
Select the View tab.
Check "Show hidden files and folders" and un-check "hide protected operating system files"
Compare the working drive and non-working drive(s) boot.ini contents.
Another comparison between the good and bad drives:
The exact size and modified dates of the ntldr file also on the root of C:.
Desktop: A confirmation that all 3 drives are configured for Primary (via jumpers/cable select and BIOS) and connected to Channel 0 (IDE 0).
If notebook, you may need to use the XP CD and boot to the recovery console to gain acess to the files.
Good Luck !